Electromigration evaluation methodology with consideration of current distribution

Abstract

The present disclosure provides a method for evaluating a heat sensitive structure. The method includes identifying a heat sensitive structure in an integrated circuit design layout and identifying a heat generating structure in the integrated circuit design layout. The method also includes calculating an operating temperature of the heat generating structure by taking a practical current distribution into consideration. The method also includes calculating an anticipated temperature increase for the heat sensitive structure induced by thermal coupling of the heat generating structure at the operating temperature.

What is claimed is: 
     
       1. A method for evaluating a heat sensitive structure, comprising:
 identifying a heat sensitive structure in an integrated circuit design layout; 
 identifying a heat generating structure in the integrated circuit design layout; 
 calculating an operating temperature of the heat generating structure by taking a practical current distribution into consideration; and 
 calculating an anticipated temperature increase for the heat sensitive structure induced by thermal coupling of the heat generating structure at the operating temperature, 
 wherein the practical current distribution includes a first current path and a second current path running into the heat generating structure, and a current passing through the first current path is different from a current passing through the second current path. 
 
     
     
       2. The method of  claim 1 , further comprising:
 retrieving design data corresponding to the integrated circuit design layout from a database; and 
 analyzing the design data to identify the heat sensitive structure and the heat generating structure. 
 
     
     
       3. The method of  claim 1 , further comprising:
 evaluating the heat sensitive structure at an evaluation temperature based on the anticipated temperature increase. 
 
     
     
       4. The method of  claim 3 , wherein:
 the heat sensitive structure includes a conductive line; and 
 evaluating the heat sensitive structure includes an electromigration (EM) analysis of the conductive line. 
 
     
     
       5. The method of  claim 4 , further comprising:
 verifying that the conductive line passes the EM analysis; and 
 manufacturing a semiconductor device according to the integrated circuit design layout. 
 
     
     
       6. The method of  claim 1 , wherein the heat generating structure includes a fin field effect transistor (FinFET) structure. 
     
     
       7. The method of  claim 6 , wherein calculating the operating temperature of the heat generating structure by taking the practical current distribution into consideration comprises:
 determining a total current running through the FinFET structure, a polysilicon gate (PO) number of the FinFET structure, a polysilicon gate over diffusion edge (PODE) number of the FinFET structure, a source number of the FinFET structure, and a drain number of the FinFET structure. 
 
     
     
       8. The method of  claim 6 , wherein calculating the operating temperature of the heat generating structure by taking the practical current distribution into consideration comprises:
 determining a location of an individual current path of the FinFET structure; and 
 calculating a practical current for the individual current path of the FinFET structure. 
 
     
     
       9. The method of  claim 6 , further comprising:
 calculating the operating temperature of the FinFET structure by taking an oxide definition (OD) area number of the FinFET structure into consideration. 
 
     
     
       10. The method of  claim 6 , further comprising:
 calculating the operating temperature of the FinFET structure by taking a fin structure width of a fin structure of the FinFET structure into consideration. 
 
     
     
       11. The method of  claim 10 , wherein the FinFET structure includes a first fin structure having a first fin structure width and a second fin structure having a second fin structure width different from the first fin structure width of the first fin structure. 
     
     
       12. The method of  claim 1 , wherein the operating temperature of the heat generating structure exceeds a predetermined temperature level above the anticipated temperature of the heat sensitive structure. 
     
     
       13. The method of  claim 1 , wherein the current passing through the second current path is substantially twice the current passing through the first current path. 
     
     
       14. The method of  claim 13 , wherein the practical current distribution includes a third current path running into the heat generating structure, and a current passing through the third current path is substantially the same as the current passing through the first current path. 
     
     
       15. The method of  claim 1 , further comprising:
 calculating a current-induced metal heating temperature increase for the heat sensitive structure. 
 
     
     
       16. A method for evaluating a heat sensitive structure, comprising:
 identifying a heat sensitive structure in an integrated circuit design layout; 
 identifying a FinFET structure in the integrated circuit design layout; 
 calculating an operating temperature of the FinFET structure by taking a practical current distribution into consideration; and 
 calculating an anticipated temperature increase for the heat sensitive structure induced by thermal coupling of the FinFET structure at the operating temperature, 
 wherein calculating the operating temperature of the FinFET structure by taking the practical current distribution into consideration comprises: 
 determining a total current running through the FinFET structure, a polysilicon gate (PO) number of the FinFET structure, a polysilicon gate over diffusion edge (PODE) number of the FinFET structure, a source number of the FinFET structure, and a drain number of the FinFET structure. 
 
     
     
       17. The method of  claim 16 , wherein calculating the operating temperature of the FinFET structure by taking the practical current distribution into consideration further comprises:
 determining locations of a plurality of individual current paths of the FinFET structure. 
 
     
     
       18. The method of  claim 17 , wherein calculating the operating temperature of the FinFET structure by taking the practical current distribution into consideration further comprises:
 calculating self-heating temperatures for the plurality of individual current paths of the FinFET structure. 
 
     
     
       19. A method for evaluating a heat sensitive structure, comprising:
 identifying a heat sensitive structure in an integrated circuit design layout; 
 identifying a FinFET structure in the integrated circuit design layout; 
 calculating an operating temperature of the FinFET structure by taking an oxide definition (OD) area number of the FinFET structure into consideration; and 
 calculating an anticipated temperature increase for the heat sensitive structure induced by thermal coupling of the FinFET structure at the operating temperature, 
 wherein the FinFET structure includes a first OD area and a second OD area spaced apart from the first OD area. 
 
     
     
       20. The method of  claim 19 , wherein the first OD area has a first OD area width and the second OD area has a second OD area width different from the first OD area width of the first OD area.